Homemade Epilog rotary

[David McHenry]

I had a guy build me a rotary for my Epilog 40 watts and after 6 months and getting ripped off I finally received it. Here's my problem. Besides the crappy design the scale is not correct. The reason I wanted a custom rotary is that I want one with a chuck and I do not have the time to build it myself.

When I tested this I used a .5 in dowel and set the page to 1.57 (D x pie). My first run on when about 40% around the dowel. By increasing the page vertical setting I also most got it to burn completly around the dowel but the pages seting was at 4.5 inches to burn around a .5 dowel.

Heres what I know. The rotary is using a vexta stepper P/N:PK266-02A. This stepper is 1.8 deg but Epilog uses a .9 deg step. Also I did not count the teeth on the gears but the gear on the stepper is very small and the gear on the shaft of the chuck is very large. So large that the laser head will hit it if I'm not careful. Another issue it that the motor is mounted so close to the chuck the if I open the jaws any larger than .5 inches the back og the jaws hit the motor.

I'm thinking of changing the stepper motor to Epilogs model with the .9 deg step, changing the gears and relocating the motor further away. Basically I need to completely redesign this thing.

My question is do I need to go to a .9 stepper and does any one have the size of the gears or the radio. I read somewhere that it was 6 to 1 but if someone has one to measure I'd fell better about buying them. I'm already out quite a bit of money. . I'll upload some pics later tonight so you guys can see what I have.

Thanks

Dave

[Dan Hintz]

I would think the cheapest method is to replace part of the gear train for an extra divide-by-2...

[Gary Hair]

Dave,
I think you could use the stepper that came with it if you change the gear ratio. Sorry that I don't know what it would be, but it must be possible, no use change the stepper and the gears.

Gary

edit: apparently Dan and I were typing at the same time, he was just a bit quicker than I was...

[George D Gabert]

Just food for thought.

I do not know much about the Epilog print driver, but most print drivers have a multiplier/calibration from actual dimension to print dimension. Change the default until you get the vertical units to match the full diameter you are looking for when using your rotary.

GDG

[Joe Hillmann]

Can the epilog print driver be used to drive a rotary with a chuck? I assume since in the epilog rotary the part just sits on the rollers and if the rollers turn one inch the part will turn one inch it doesn't have a spot in the driver to program for the diameter of the object, and also that it will be spinning in the wrong direction. Whereas with a rotary with a chuck you program it for every item based on its diameter so the print driver can then figure out degrees into inches.


Trying to explain this a little better.

With the epilog it looks like one inch equals about 57 degrees no matter what the diameter of the work piece is because the degrees per inch is biased on the diameter of the drive wheels.

With a universal rotary (with a chuck) one inch on a one inch diameter work piece is about 114 degrees and one inch on a 3 inch piece is about 38 degrees and the print driver has to be able to figure that out.

Although you could get around that by making it the size you want it then stretching it what ever percentage of 2 inches that your work piece is and then mirror it up and down. It would look very messed up on screen but would come out correct on the part. (that is assuming the epilog print driver doesn't ask what the diameter of the part is)

[Glen Monaghan]

I'm amazed you ever got anything from him!

You can either change the gearing or change the stepper if you want to match the Epilog rotary, but realize that you'll have to scale designs according to the engraved item's diameter/circumference with a chuck, unlike with a roller design.

FWIW, it is common to overdrive steppers, often 2x to 3x. However, that stepper is rated 5V and Epilog's drivers are 48V without current modulation. So, you are overdriving the motor almost 10x and undoubtedly maxing out the driver's ability to supply current and generating a lot of heat and stress...

-Glen

[Leon Sandstrom]

Just curious...where would a chuck type drive be better? Are you trying to engrave bowls turned on a lathe where they won't sit on the rollers without sliding? Seems to me a chuck would just get in the way unless the piece was bigger diameter than the chuck itself. What are you wanting to engrave exactly? You really got me thinking about the uses for a chuck system, but the only thing I can think of is big diameter bowls with a shallow depth.

Leon

[David McHenry]

Glen,
I kind of figured the stepper was rated to small for an Epilog. I'm going to see about replacing it because of the voltage rating. I dont know how common a 48 v is but I'll be starting a search tomorrow. I got the gears off tonight and broke the larger one. Looks like Bill didn't want it taken apart. My check is also stuck. The threads were loose on the chuch and there is not backing plate so if you tighten it up it jams up agains the mount. For the gear ratio I glued a nail to the end of the stepper motor and began the exciting process of counting how many times it turns. Here is what I found.
1.5 turns = 1 inch
3 turns= 2 inches
6 turns= 4 inches
6.75 turns = 4.5 inches
and I think 1 turns = .75 inch if i wrote it down correctly.

The gear on the stepper was 20 and the one on the chuck was 130. I think that 1 to 6.5 but I'll never know because I broke the gear. Stepper motor shaft was bent when I received it also. I wrote down the wiring and took picture but its to late to post. I think the only reason Bill sent me the rotary is because I got him 3K for making an item for my company in which he only delivered half and the work was shotty. For the chuck I want it to egrave around pens and such but mostly for doing some inlay on pens. I'm in the for $500 so I'll throw so more money at it and get it to work. What get me is that is was farily easy for me to get the gear ratio. Bill must has used just any gear laying around his shop to put on the rotary. Sad thing is that is does work even if the motor and gear ratios are wrong.

[David McHenry]

Sorry about the spelling in the above post.......time for bed

[Leon Sandstrom]

If for inlay on pens, then the only solution outside of the manual step is to have like blanks for the different type of wood and cutting the pieces separate. It is possible. Easy with CNC machine. If just relying on engraver, your lathe work better be good. You don't need a chuck to do this, just Martel much the same as you would use on the lathe to sit in the regular rotary made by Epilog. Again though, the closer you are to like blanks, the better. The problem is the angles created based on the diameter of each separate wood being cut. I see another patent coming soon if you figure it out. Of course now a days you can patent an idea before it actually works. Those with money do it all the time. Haven't looked, but probably already done. Always wondered how engraving cigars could be a patent. Anyone can do it but can't sell online without paying the first guy to do it because he patent the idea. Not fair in my eyes. Then again maybe I just read it wrong. For that matter, if you engrave on a leaf I think they can come after you for money.

[Glen Monaghan]

For the gear ratio I glued a nail to the end of the stepper motor and began the exciting process of counting how many times it turns. Here is what I found.
1.5 turns = 1 inch
3 turns= 2 inches
6 turns= 4 inches
6.75 turns = 4.5 inches
and I think 1 turns = .75 inch if i wrote it down correctly.

From what you've shown here, 1 turn = 2/3 inch (0.6666...) as in 3 turns/3 = 2 inches/3 or 1 turn = 2/3 inch

-Glen

[Leon Sandstrom]

Not trying to hijack the thread, just think this would work for pen inlays on the normal rotary. Have to admit am interested in seeing your chuck unit. Not enough smarts on my end to dive into a project like that.

[Joe Hillmann]

Glen,

1.5 turns = 1 inch
3 turns= 2 inches
6 turns= 4 inches
6.75 turns = 4.5 inches
and I think 1 turns = .75 inch if i wrote it down correctly.

All of these turns to inches is only accurate at a single diameter, Unless you are going backwards and actually mean inches in coral draw to turns of the chuck.

[Joe Hillmann]

Just curious...where would a chuck type drive be better? Are you trying to engrave bowls turned on a lathe where they won't sit on the rollers without sliding? Seems to me a chuck would just get in the way unless the piece was bigger diameter than the chuck itself. What are you wanting to engrave exactly? You really got me thinking about the uses for a chuck system, but the only thing I can think of is big diameter bowls with a shallow depth.

Leon

The chuck doesn't have any slippage so when you go back to 0 you run the same job a second time on the part and it will be in the exact same spot. You can also do items with handle or items that aren't round, you can do items with a large taper or items that can only be clamped on one end, you can do very narrow items such as rings or bracelets or the edges of a coin. You can advance it a set number of degrees or distance so you can line it up with something that is already on the part. About the only place that I have found it fall short so far is if I want to wrap a design around an object more than once.

[Leon Sandstrom]

Gotcha, I wasn't thinking out of the box. Can definetly see the advantages. Best of luck figuring it out. And when you do, I'd be interested in buying one. Never have to many toys.